Automatic bow sight

ABSTRACT

This invention relates to a bow sight and more particularly, but not exclusively, to an automatic bow sight which is releasably securable to a bow. The bow finder includes a range finder, a range finder aiming mechanism for use in assisting to aim the range finder at a target, a display arrangement including a plurality of fight sources that can be switched on independently and/or in combination, and a processor configured to receive information from the range finder, and to send an actuation signal to the display arrangement in order for at least some of the light sources to be selectively switched on.

BACKGROUND TO THE INVENTION

This invention relates to a bow sight and more particularly, but not exclusively, to an automatic bow sight which is releasably securable to a bow.

A bow sight is an accessory that is typically mounted on a riser of a bow, and which assists an archer with aiming, and in particular in adjusting the trajectory of an arrow over longer distances. Bow sights greatly increases accuracy and consistency, and there has accordingly been significant development of bow sights in recent times.

One type of basic bow sight comprises a plurality of pins that, in use, protrude from the riser of the bow, with each pin being associated with a particular distance. The distances are established during the shooting in or sighting of the bow. When an archer wants to take a shot, the distance to the target is estimated, and the relevant pin is used as an aiming aid.

Range finders are commonly used to determine the distance to a target, and in some cases are also attached to the riser of the bow. A user can then accurately determine the range of the target, and use such determination to select the correct shooting pin. For example, U.S. Pat. No. 4,753,528 comprises a bow sight with a range finder attached thereto, as well as a means of reading and displaying the range to the target which then allows the archer to decide which shooting pin to use, without having to first range the target with a separate ranging device.

There have been many attempts to automate bow sights so that adjustments and selections are done automatically, and without the potential for significant user error. Existing systems of this nature typically share the common denominators of a range finder being mounted on a bow, and the output from the range finder being used by a processor to determine a correct aiming pin or other aiming device.

U.S. Pat. No. 4,894,921 discloses an archery range finder sight comprising a housing affixed onto the bow, and a bow sight element employing a number of sight pins vertically spaced above one another and mounted on the housing. A number of LED's or lamps are mounted on the housing so as to be visible to the archer when aiming the bow. Once the target has been ranged one of the lamps becomes illuminated to indicate the range to target, and the bow is aimed using and shot according to a respective one of the sight pins associated with the particular LED. Likewise, U.S. Pat. No. 6,073,352 discloses the use of a range finder on a bow that would activate a LED for a measured distance. Light from the LED is then transmitted via an optic fiber to highlight the corresponding shooting pin. In both the above one would require a plurality of shooting pins, which have been previously been shot in and adjusted. A disadvantage of these sights is that they include a plurality of shooting pins that protrudes into the sight window of the sight, which then obscures the target and accordingly adversely impact on the ease and accuracy of aiming.

U.S. Pat. No. 8,276,282 sets out to at least partially overcome this shortcoming by introducing an automatically adjustable shooting pin, the position of which is adjusted (for example by way of a stepper motor) in response to an input signal received from a range finder. Similarly, U.S. Pat. No. 8,166,962 also makes use of an adjustable shooting pin. While U.S. Pat. No. 8,276,282 and U.S. Pat. No. 8,166,962 disclose automatic bow sights that have a shooting pin arrangement with limited visual interference, the adjustable shooting pin is in the form of a mechanically driven and actuated pin, which results in reduced reliability in the often arduous hunting conditions. Ingress of dust and moisture can, for example, adversely impact on the actuator. The mechanisms are also prone to significant wear due to the presence of moving parts, and can also be noisy, which is obviously not ideal in the hunting environment. Finally, even though the visual obstruction is less than that encountered with conventional multi-pin sights, there is still a pin that protrudes into the field of view of a user, even though only the tip of the pin is actually required for the purposes of aiming.

Other examples of automated bow sights use LCD displays (or other similar displays) instead of shooting pins. U.S. Pat. No. 7,614,156 discloses a bow-mounted sight with range finder and data storage means, and which uses a range-finding device to range, and with the ranged data will set cross hairs in the correct shooting position making use of a LCD display. U.S. Pat. No. 6,952,881 discloses a programmable sighting system for a hunting bow, which makes use of a LCD display to project an image on a see-through lens and call the process (HUD) heads up display. The display displays various shooting information to the archer, which will in turn assist the archer in estimating a range to the target, but this system does not include any automated ranging functionality. U.S. Pat. No. 8,316,551 discloses an auto-correcting bow sight. The bow sight is similar to that disclosed in U.S. Pat. Nos. 7,614,156 and 6,952,881, except that in this case the display is one of either transparent LCD, transparent OLED, Transparent FSTN, or a LED array positioned vertically and horizontally in the sight window, as well as a matrix of optic fibers that carry light from LED's.

U.S. Pat. Nos. 8,316,551, 7,614,156, 6,073,352 and 4,894,921 all disclose an automatic bow sight, using a range finder, processor and accelerometer to range a target, process the information and present a shooting indicator. The method of displaying the shooting indicator (pin) is one of using either LED's (Light emitting diodes), see through or transparent LCD's, (Liquid crystal display), OLED's (Organic Light emitting diodes), FSTN's (Fast supertwist nomatic) or even optic fiber meshes or networks coupled to LED's to display the shooting pin and or numeric shooting information. The problem with using any of these transparent displays is that, although they can work in low light conditions, there usability is seriously compromised in sunny conditions, an effect which is for example also apparent when using on cell phones and other electronic displays. A further shortcoming of the proposed bow sights is that the presence of LED's or optic fibers positioned directly in the display area or sight window will obscure the view of the archer in much the same way as what is experienced with shooting pins, as discussed above.

Another significant problem associated with existing automatic sights is that it is often very difficult to ensure that the range finder is focused on a correct target. For example, the archer may think that the range finder is ranging a buck, but the range finder may actually be focused on, and hence ranging, a rock or a bush behind the buck. This is because the range finder is mounted on the bow, and is not used in a normal handheld configuration where the eye of the user is in close proximity of the range finder. In other applications where range finders are often used, for example golf or rifle hunting, this issue does not arise, because there is no issue with using a range finder which requires a user to aim the reticle at the target, and which therefore require the eye of the user to be located immediately adjacent an eyepiece of the rangefinder.

In all the automatically adjusted bow sights mentioned above making use of a rangefinder, the method of ranging the target is to line up the peep at full draw of the bow with some sort of marker or cross hair positioned on the sight. The marker and range finder are said to be pre-aligned in the assembly process. A first disadvantage of this methodology is that all archers do not have the same draw. If an archer has a longer or shorter draw than another, or positions his peep higher or lower than another, the angle from the peep to the marker will differ, and this could cause the archer to inaccurately range an object either behind or in front of the intended target, causing him to either wound or totally miss the target. A further disadvantage is that with this this methodology ranging can only take place at full draw. This is a disadvantage as unnecessary movement and/or drawing the bow raises the risk of chasing the animal while hunting.

It is accordingly an object of the invention to provide an automatic bow sight that will, at least partially, alleviate the above disadvantages.

It is also an object of the invention to provide an automatic bow sight which will be a useful alternative to existing automatic bow sights.

SUMMARY OF THE INVENTION

According to the invention there is provided a bow sight including:

-   -   a range finder suitable for determining a range to a target;     -   a range finder aiming mechanism for use in assisting to aim the         range finder at a target;     -   a display arrangement including a plurality of light sources         that can be switched on independently and/or in combination; and     -   a processor configured to receive information from the range         finder, and to send an actuation signal to the display         arrangement in order for at least some of the light sources to         be selectively switched on.

There is provided for the range finder aiming mechanism to be in the form of a laser guide which is aligned with the range finder in order to provide, in use, a visual indication of a focal point of the range finder.

There is provided for the range finder aiming device to be in the form of a laser beam used by the range finder to range a target.

There is provided for the range finder, laser guide, processor and display arrangement to be securable to a bow, and more particularly to a riser of a bow.

In one embodiment there is provided for the laser guide and the range finder to be part of the same device, with the visible laser used for aiming also being the source used for ranging.

There is further provided for the automatic bow sight to include a housing configured for housing the range finder, laser guide, processor and display arrangement, the housing being releasably securable to the bow.

The housing may include a sight window for housing the display arrangement, a range finder and laser guide enclosure located operatively above the sight window, and a processor enclosure operatively adjacent the sight window.

A further feature of the invention provides for the display arrangement to include a display element from which light emanating from the light source is reflected toward the archer.

The display element is preferably in the form of a layer of transparent material that is orientated at an angle relative to a line of sight of the archer.

The line of sight of the archer may be defined by an axis protruding perpendicularly from the sight window of the bow sight.

A bow plane may be defined as a plane that extends through the middle of a riser and upper and lower limbs of the bow. There is provided for the display element to be inclined relative to the bow plane. An angle of inclination may be between 30 and 60 degrees, preferably between 40 and 50 degrees, most preferably 45 degrees.

There is provided for the light sources to be located operatively towards the side of the display element, in order for light emitted from the light sources to be, in use, reflected in the direction of the user. The light sources may be located in a vertical sidewall of the sight window.

The light sources may be in communication with the processor located in the processor housing adjacent the sight window.

More particularly, the light sources may be mounted on a PC board of the processor, and light emitted from the light sources may be projected into the sight window though slots and/or apertures located in a sidewall of the sight window.

The light sources may include an array of vertically spaced apart LED's, more particularly micro LED's, which can be used to project an aiming dot onto the display element.

The light sources may also include a combination of seven segment LED's than can be used to project numerals onto the display element. There is also provided for text to be displayed in addition to numerals, but this will not necessarily be the case.

A further feature of the invention provides for the bow sight to include a magnification lens for magnifying the view through the sight window.

There is also provided for the housing to include a receiving formation suitable for releasably receiving a magnification lens.

A further feature of the invention provides for the processor to include a memory module for storing a plurality of pre-set shooting programs to enable a user to choose one of the pre-set programs when the bow is sighted.

In one embodiment of the invention the bow sight may also include an inclinometer and/or accelerometer for use in determining the inclination of the bow, which information may be fed to the processor for further processing.

In one embodiment of the invention that bow sight may also include a levelling instrument, preferably a spirit level, for assisting in ensuring that the bow is held in a vertical orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention is described by way of a non-limiting example, and with reference to the accompanying drawings in which:

FIG. 1 is a schematic side view of an archer using a bow being fitted with a bow sight in accordance with one embodiment of the invention;

FIG. 2 is a front perspective view of the bow sight in accordance with the invention;

FIG. 3 is a rear perspective view of the bow sight of FIG. 2;

FIG. 4 is a rear view of the bow sight in use; and

FIG. 5 is a cross-sectional top plan view of the bow sight of FIG. 2.

DETAILED DESCRIPTION OF INVENTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings and are thus intended to include direct connections between two members without any other members interposed therebetween and indirect connections between members in which one or more other members are interposed therebetween. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. Additionally, the words “lower”, “upper”, “upward”, “down” and “downward” designate directions in the drawings to which reference is made. The terminology includes the words specifically mentioned above, derivatives thereof, and words or similar import. It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

Referring to the drawings, in which like numerals indicate like features, a non-limiting example of an automatic bow sight in accordance with the invention is generally indicated by reference numeral 20.

The automatic bow sight 20 can be mounted on many kinds of bows, for example a composite bow as shown in FIG. 1. A composite bow 10 comprises a riser 11 that holds a grip, and which is also a middle part of the compound bow 10. A pliable upper limb 12 and a pliable lower limb 13 extend from the riser 11 and store the energy that is generated when the bowstring is pulled back. In this specification, the bow plane 18 is defined as a plane that extends through the centers of the riser 11, the upper limb 12 and the lower limb 13 (the bow plane is indicated in FIG. 4). Cams 14 are attached to the ends of both the lower limb 13 and the upper limb 12 and in use carry the bowstring 15. A sight 16 is provided on the riser 11 to assist with aiming of the bow, and a corresponding peep sight 17 is provided on the bowstring 15 allowing the archer in use to look through the peep sight 17 as well as the sight 16 on the riser 11.

In this invention, the conventional sight (not shown) is replaced with and/or augmented by an automatic bow sight 20, which is described in more detail hereinbelow.

The bow sight 20 includes a housing 30 for housing all the different components of the automatic bow sight 20. The housing 30 includes a sight window 31 inside which a display arrangement 40 is located. The sight window 31 includes a window opening 31.1 through which an archer will in use look. The sight window 31 is in the form of a substantially cylindrical channel having a planar inner sidewall 31.2. A vertically extending sight window slot 31.3 is provided in the inner sidewall 31.2, and a further sight window display opening 31.3 is located operatively above the sight window slot 31.3. A rangefinder and laser enclosure 33 is located above the sight window enclosure 31, and is adapted to house a rangefinder 60 as well as an aiming laser 70. A rangefinder aperture 33.1 and a laser aperture 33.2 are provided in a front wall of the rangefinder and laser enclosure 33. The processor housing 34 is located adjacent the sight window enclosure 31, and more particularly next to the inner sidewall 31.2 of the sight window. A vertical slider bracket 35 and a horizontal slider bracket 36 extend from the housing, and are used to secure the housing 32 to the bow 10, and more particularly to a riser of the bow 10.

A rangefinder 60 is located inside the rangefinder and laser enclosure 33, with optical elements of the rangefinder 60 being aligned with the rangefinder apertures 33.1 of the enclosure. A range finder aiming device, in this embodiment in the form of a laser emitting device 70, is also located inside the rangefinder and laser enclosure 33, with the optical element of the laser emitting device 70 being aligned with the laser aperture 33.2. The laser emitting device 70 and the rangefinder 60 are factory aligned in order for the laser to act as a visual guide to ensure that the rangefinder 60 is used to range the correct object. The laser emitting device 70 will project a small but very visible dot on the target, which will tell the user that the correct object is being ranged. In this embodiment the rangefinder 60 and the laser emitting device 70 are shown as two independent objects, but it will be appreciated that they can also be combined into a structurally single device including both a range finder aiming device in the form of a laser emitting device 70 and a rangefinder 60 that emits infra-red light. Furthermore, the laser may in itself also be used as the range finder ranging light source, and the distance measurement calculated from the reflection of the colour laser instead of the conventional infra-red light source.

It will be appreciated that range finders were designed with military requirements in mind, and have been developed with the intention of not being visible when in use. Range finders typically utilize ultra-violet or infrared beams that are aimed at a target using a pre-aligned reticle. It is therefore not obvious for a targeting range finder simply to be modified to use a visible light source, which will still have sufficient energy and visibility in sunny conditions.

A display arrangement 40 is located inside the sight window 31 of the scope. The display arrangement 40 includes a display element 41 in the form of a glass screen that is located inside the sight window 31. The glass may for example be a 2 mm thick tinted glass, and may be manufactured with the tint on one side to allow the clearly projected dot and numeric information to be reflected back to the archer. The glass screen is located at an angle relative to a line of sight 19 of a user, and also relative to the bow plane 18 as defined above. In one embodiment the glass screen is orientated at an angle (0) of about 45° relative to the line of sight 19 and the bow plane 18. The effect of the angular orientation of the glass screen is that a user will still be able to see through the glass screen when looking along the line of sight 19, while light emitted by a light source on the side of the glass screen will be reflected through 90° towards the user, and will therefore also be visible along the line of sight 19. In this way reflected information, like an aiming dot 43 or other numerical information 44, can be superimposed over the actual view 42 as seen by the user.

The above is achieved by providing a plurality of light sources 90 at the side of the display element or glass screen 41. In practice this is achieved by providing at least one light source 90 inside the processor housing 34, and allowing light emitted by the light source 90 to shine onto the display element 41 through a sight window slot 31.3 or a sight window display aperture 31.4 provided in the sight window sidewall 31.2. The light will then be reflected by the oblique display element 41 towards a user. In this example the light source 90 includes an array of micro-LEDs 91 which will in use display an aiming dot 43 on the display element 41, as well as a number of seven segment LEDs 92 which will in use display numerical information and possibly also text on the display element 41.

A magnification lens 50 may be releasably secured to the housing 30, and more particularly to an opening 31.1 of the housing 30. The magnification lens 50 will magnify the target, and the curvature of the magnification lens 50 will be compensated for by the processor of the bow sight 20.

A processor 80 is located inside the processor housing 34. The processor 80 may be in the form of a double sided circuit board that incorporates a memory module, controller, and other electronic components which will assist in the processing of information pertaining to the distance and shooting angle. The processor may also, but not necessarily, include an accelerometer or inclinometer, but if this is not present the vertical orientation of the bow and the resultant change in trajectory will be mathematically computed and incorporated into the various control models. An accelerometer or inclinometer is therefore by no means an absolute requirement for this invention.

A number of preset programs will be loaded onto the memory module of the processor. These preset programs are all pre-designed, and cater for the trajectory of different weighted arrows and speeds and draw—lengths of the different bows used by archers. During the sighting process the archer will select a program that is best suited for his set up, and once tested through various ranges the program will be stored as the preferred program for that particular set up. The archer may have several programs stored for different set ups according to the weight and speed of the arrows he might be using. These programs can also be viewed and adjusted, when the bow sight is plugged into a computer, via an interface program provided. A desired preset program will be selected during the sighting of the sight.

It is not foreseen for any real time modelling to be performed by the processor, and the processor will merely receive a distance input from the rangefinder 60 and in response will illuminate the correct light source 90 in accordance with the preset program that was chosen during the sighting of the sight. No additional variables, for example the weight, type and dimensions of a particular arrow, needs to be programmed into the system, as the processor functions on a preset program selection methodology, as opposed to an involved real-time calculation methodology. Micro switches 80.1 are provided on the PC board of the processor and will be accessible through the cover of the housing 30, thus allowing one manually to include a range in order to display the shooting dot 43. This will allow the user to use the sight 20 in cases where the rangefinder and/or the laser may not be used. As mentioned above, some of the preset programs will also be specifically configured to compensate for the effects of curvature of the magnification lens 50 in cases where such lens is fitted to the housing 30.

All electronic components with exception of the micro LED's and seven segment LED's will be cast in potting compound, firstly to make the sight water resistant and secondly to help absorb any shock that may reverberate through the bow. The LED's and seven segment displays will be potted using a transparent compound.

A trigger button (not shown) is fastened to the bow handle, and is electrically connected to the processor by means of a cable (not shown). The user can activate the button without changing his hand position on the bow, or finger position on the handle. The button can furthermore be triggered, and the sight activated, without the bow being at full draw.

In use, a user sights the bow using a normal sighting tape procedure as is well known in the art. Predetermined programs are created on a computer, and uploaded onto the PC board of the sight before the sight is sold to a user. Based on the sighting procedure, one of these predetermined and preloaded programs is elected that matches the particular archer, bow and arrows used. Once so sighted and programmed the bow with automatic bow sight is ready to be used. The user can now aim the bow at a target using the bow sight, and when the trigger button is pushed the laser will emit a laser guide light which will be visible on the target. The rangefinder will then range the particular target, and the user will know that the correct target is ranged due to the laser guide and the rangefinder being factory aligned. The rangefinder will provide a distance to the processor (which is now set on a predetermined program as per sighting of the bow) and will display a reflected aiming dot on the oblique screen. At the same time additional numerical information (such as the actual range) will also be displayed on the oblique screen. The user can now draw the bow, and attempt to hit the target. The ranging can of course also be done whilst the bow is fully drawn, but advantageously this is not necessary as the rangefinder does not have to be aligned using the peep of the bowstring like in some other prior art products.

The new bow sight is advantageous over the prior are because it is, inter alia:

-   -   fully digital and therefore far more reliable than other         automatic and semi-automatic sights;     -   the design is simple to operate in the drawn/undrawn position,         and water proof;     -   the product will handle reasonable abuse in the field;     -   the shooting dot is a very small but clearly visible blue dot,         even in bright outside conditions, giving the archer a clear         view of the target; where other methods because of physical size         or non-clarity obscure the target;     -   the product is more compact and substantially lighter than         competing devices. The display in the present invention differs         significantly from all the existing displays in that an array of         miniature LED's is used for the shooting dot, with the LED's         being individually driven and projected onto a tinted oblique         glass screen that forms the display. In addition, surface         mounted seven segment LED displays are also projected onto the         same tinted glass. The glass is positioned at 45 degrees to the         LED's and seven segment LED displays, so as to reflect the         shooting dot and numeric shooting information back to the archer         without moving the display off the target.

The glass, although tinted, is still about 80% transparent, allowing the archer to have clear vision of the target, with only a tiny very visible blue dot being superimposed onto the intended target. The shooting information is cleared off the display by the time the archer is ready to take the shot. Reflecting the light source as per the current design produces a very high quality display which is visible in any light condition. Having the tinted glass at 45 degrees also improves the sight in that it does not reflect any light towards the target, which will be the case in the other lenses. Also, with the present sight the user can point the laser at the target and get a range without drawing or loading an arrow, or if the user wants to he can also take a range at full draw.

It will be appreciated that the above is only one embodiment of the invention and that there may be many variations without departing from the spirit and/or the scope of the invention. It is easily understood from the present application that the particular features of the present invention, as generally described and illustrated in the figures, can be arranged and designed according to a wide variety of different configurations. In this way, the description of the present invention and the related figures are not provided to limit the scope of the invention but simply represent selected embodiments.

The skilled person will understand that the technical characteristics of a given embodiment can in fact be combined with characteristics of another embodiment, unless otherwise expressed or it is evident that these characteristics are incompatible. Also, the technical characteristics described in a given embodiment can be isolated from the other characteristics of this embodiment unless otherwise expressed. 

1. An automatic bow sight including: a range finder suitable for determining a range to a target; a range finder aiming mechanism for use in assisting to aim the range finder at a target; a display arrangement including a plurality of light sources that can be switched on independently and/or in combination; and a processor configured to receive information from the range finder, and to send an actuation signal to the display arrangement in order for at least some of the light sources to be selectively switched on.
 2. The automatic bow sight of claim 1 in which the range finder aiming mechanism is in the form of a laser guide which is aligned with the range finder in order to provide, in use, a visual indication of a focal point of the range finder.
 3. The automatic bow sight of claim 1 in which the range finder aiming device is in the form of a laser beam used by the range finder to range a target.
 4. The automatic bow sight of claim 1 in which the range finder, laser guide, processor and display arrangement are securable to a bow.
 5. The automatic bow sight of claim 4 including a housing configured for housing the range finder, laser guide, processor and display arrangement, the housing being releasably securable to the bow.
 6. The automatic bow sight of claim 5 in which the housing includes a sight window for housing the display arrangement, a range finder and laser guide enclosure located operatively above the sight window, and a processor enclosure operatively adjacent the sight window.
 7. The automatic bow sight of claim 6 in which the display arrangement includes a display element from which light emanating from the light source is in use reflected towards the archer.
 8. The automatic bow sight of claim 7 in which the display element is in the form of a layer of transparent material that is orientated at an angle relative to a line of sight of the archer and relative to a bow plane.
 9. The automatic bow sight of claim 8 in which the display element is inclined at an angle of between 40 and 50 degrees relative to the bow plane.
 10. The automatic bow sight of claim 9 in which the display element is inclined at an angle of approximately 45 degrees relative to the bow plane.
 11. The automatic bow sight of claim 8 in which the light sources are located operatively towards the side of the display element, in order for light emitted from the light sources to be, in use, reflected in the direction of the user.
 12. The automatic bow sight of claim 11 in which the light sources are located in a vertical sidewall of the sight window.
 13. The automatic bow sight of claim 1 in which the light sources are in communication with the processor located in the processor housing adjacent the sight window.
 14. The automatic bow sight of claim 13 in which the light sources are mounted on a PC board of the processor, and light emitted from the light sources is projected into the sight window though slots and/or apertures located in a sidewall of the sight window.
 15. The automatic bow sight of claim 14 in which the light sources may include an array of vertically spaced apart LED's which can be used to project an aiming dot onto the display element.
 16. The automatic bow sight of claim 15 in which the light sources also includes a combination of seven segment LED's than can be used to project numerals onto the display element.
 17. The automatic bow sight of claim 1 including a magnification lens for magnifying the view through the sight window.
 18. The automatic bow sight of claim 1 including a receiving formation suitable for releasably receiving a magnification lens.
 19. The automatic bow sight of claim 1 in which the processor includes a memory module for storing a plurality of pre-set shooting programs to enable a user to choose one of the pre-set programs when the bow is sighted.
 20. The automatic bow sight of claim 1 including an inclinometer and/or accelerometer for use in determining the inclination of the bow, which information may be fed to the processor for further processing.
 21. The automatic bow sight of claim 1 including a levelling instrument for assisting in ensuring that the bow is held in a vertical orientation. 